Angela Merkel's ruling CDU party has been beaten into third place by the anti-migrant Alternative für Deutschland (AfD), according to an exit poll following elections in a German state.
The right-wing populist party is projected to overtake the CDU in the north-eastern German state of Mecklenburg-Vorpommern, Ms Merkel's own constituency.
Chancellor Merkel's refugee policies were a prominent issue in the campaign for Sunday's election, which came a year after she decided to let in migrants from Hungary.
Germany registered more than 1 million people as asylum-seekers last year.
Local AfD leader Leif-Erik Holm told supporters: "Perhaps this is the beginning of the end of Angela Merkel's chancellorship today."
The AfD, however, fell well short of its aim of becoming the strongest party, and also didn't match the 24.3 percent support it won in another eastern state, Saxony-Anhalt, in March.
Earlier in the year, the centre-right CDU party was expected to help form the region's coalition government along with the centre-left Social Democratic Party (SDP) mirroring the arrangement at the federal level.
The exit polls for ARD and ZDF public television put support for the AfD, in Sunday's election for the state legislature around 21 percent. They put support for Merkel's Christian Democrats at 19 or 20 percent.
There's no realistic prospect of AfD going into government.
